Initialism of phenolsulfonphthalein.
"The psp test was administered to evaluate liver function by measuring how quickly the dye cleared from the body."
In plain English: PSP stands for PlayStation Portable, which is an older handheld video game console that lets you play games on your palm anywhere.
"He bought a used psp to play games on his commute home."
Initialism of personal software process.
"The PSP is a lightweight framework designed to help individual developers improve their estimation and planning skills without adding excessive overhead."